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Old 07-07-2017, 07:51 PM   #7
Sweetc10
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Join Date: May 2016
Location: Houston texas
Posts: 51
Re: 4.8 carb tuning help

Quote:
Originally Posted by 68Stepbed View Post
I'm not familiar with the Summit carbs, but I'll help the best I can.

A few questions and suggestions first.
1: Your timing seems kind of low. My cam is slightly more aggressive, but most carbed applications I've seen use more timing. I had my timing set a 38* all in by 1200 rpm and held flat all the way past the rev limit. Is there any particular reason to back the timing back off after 4400rpm?

2: What's your thermostat temperature, and what's the typical operating coolant temp?

3: Vacuum or mechanical secondaries?

4: As geezer mentioned, power valve and idle vacuum numbers are important.

We can move forward once we have this info.
Vacuum secondaries. Thermostat 180 and truck stays right around there.
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